I just went through the license and terms (in finnish) and it reads roughly translated that "This announcement is not valid and welcome screen WILL NOT open on first run and NO sms is sent if the service is not available at your country, in your version of software or in chosen language."

So most likely you who didn't get the welcome announcement or don't have subscribe active won't be able to unsubscribe either - you haven't been subscribed at all in the first place? I can re subscribe even though I already did.